Terrorism poses the biggest threat to the holding of a successful Beijing Olympic Games, Minister of Public Security Zhou Yongkang said on Monday and called for closer international collaboration on information sharing and risk analysis.

"Although the general security situation for the Beijing Olympics remains stable, we still face the challenges of terrorism, separatism and extremism," the minister said.

"Terrorism, in particular, poses the biggest threat."

He made the remarks at the International Conference on Security Cooperation for the 2008 Beijing Summer Olympics, which saw the participation of more than 140 representatives from 32 countries and regions, and international organizations such as Interpol and the Shanghai Cooperation Organization.

Liu Jing, vice-minister of public security, told the meeting that some regional and ethnic conflicts in the world might cast a shadow over the Games, and some international terrorist or extremist groups might make use of the event to launch attacks for their own purposes.

"The Olympic Games is a happy gathering for people from all countries, but it's also a big target for terrorism," he said.

The vice-minister noted that some organizations and individuals had tried to politicize the Olympics and intervene in China's internal affairs, and some others were planning to disrupt the Olympic torch relay.

Emergencies such as stampedes and disturbances by football fans are also possible, he added.

Both officials stressed the importance of closer international cooperation as terrorism was a threat to all countries.

Zhou proposed more information exchange in the global community, and the establishment of an early risk warning mechanism. He said China would also learn from other countries to work out detailed emergency plans for the Games.

Liu said he hoped all countries and regions help safeguard the 130-day torch relay as it goes through 135 cities.

However, the Chinese police authorities said they were confident and capable of ensuring a safe Olympic Games.

"Preparation for the security work is advancing smoothly," Liu said.

Ministry reports show that security headquarters have been set up in all cities that will hold Olympic events.

More than 500 detailed security plans have been mapped out, covering Olympic venues, anti-terrorism, information exchange and security for celebrities.

Ma Zhenchuan, director of the Beijing public security bureau, told the meeting that at least 80,000 people would be directly involved in the security for the Games, including police officers, professional security guards and volunteers.

Ma said the Beijing bureau had offered professional training to 25,000 security staff; and training of the rest would be completed before the Games.